It is true that magical nature of A Song of Ice and Fire purposes a different set of quantum mechanics than our real world humans of Earth, but since you have not defined your intended definition of being human outside of a location for humans to exist (Earth), you have to consider all of the things that make someone human whether on a biological level (homo sapiens) or a conscious level (sentient) or emotional level (qualities and characteristics of human beings: social/cultural anthropology) and that doesn't necessarily rely on "where" a human is from...
IMO most of the characters presented in the work have human qualities, despite whether they are textbook human or not by reacting to their experiences in ways the reader or viewer can relate to.
However, I do think the magical nature of the universe, including characters human and/or otherwise either existing in states between life and death (Lady Stoneheart, TV series White Walkers, army of the dead), or some characters that can metaphysically transform (wargs, glamour magic, reincarnation), or are from a non-human lineage (Targaryens) are all included in the work to make us question what identity is, as there are arguments and mysteries presented through out the work about whom any of these characters really are or if what they believe is the absolute truth. There then is a question if identity or concerns over identity is also inherently a human trait?
This is furthered by notions that there may be some predetermination (ie: Hodor's Paradox) in which all of the characters may be at the expense of cycle cosmology (fate) and have little control over their fates, despite what any of them believe to be true. This doesn't really make then less human (figuratively speaking) however, because no single character is all powerful and all knowing, which is still true to how most of people of Earth experience life.